1. Field of the Invention
The present invention relates generally to tools for interior hydrostatic pressure testing of tubing, pipe, and other flow conductors. The present invention is particularly useful for interior hydrostatic pressure testing of tubing contained within a well serviced by pumpdown or through the flowline (TFL) equipment. In order to economically maintain and repair long flow conductors such as tubing in a well, it is important to locate any leaks prior to beginning a maintenance evolution. The pressure testing tool can move easily through a flow conductor until activated. Once activated, the present invention can be positioned at any desired location in the flow conductor and the flow conductor above the tool can be pressure tested. By activating the tool at one end of the flow conductor, pressure tests can be made as the tool is moved towards the other end of the flow conductor. In this manner, any leaks from the interior of the flow conductor can be located.
2. Description of the Prior Art
Interior hydrostatic testing of flow conductors such as tubing and pipe is well known. A common practice prior to inserting tubing into a well bore is to pressure test the tubing string as it is made up on the working platform. Also, most regulatory agencies require extensive hydrostatic pressure testing of pipelines before the pipeline can be placed into service.
U.S. Pat. No. 4,046,006 to A. Dufrene discloses a tubing plug apparatus for use in pressure testing well tubing. The plug apparatus is limited to wells which can be serviced by conventional wireline techniques. Also, the plug apparatus can be used only in tubing strings which have an interior collar recess for engagement by the plug.
U.S. Pat. No. 4,081,990 to J. C. Chatagnier discloses a hydraulic pipe testing apparatus which is adapted to test the joint between two sections of pipe for a leak. The testing apparatus has two packing elements which seal off on either side of the joint to be tested. Hydrostatic test fluid is injected between the two packing elements to check for leakage from the joint. The testing apparatus can not be used to test long lengths of pipe above the apparatus but only short lengths between the packing elements.
U.S. Pat. No. 4,083,230 to D. J. Rome, et al, discloses a tubing testing tool. Hydrostatic test fluid is injected between two packing elements to check for leaks in short lengths of pipe only. The testing tool also requires a separate conduit from the well surface to the tool to supply hydrostatic test pressure.
U.S. Pat. No. 3,638,723 to A. W. Carroll discloses a locator device which is activated by a reduced inside diameter portion of a well flow conductor. U.S. Pat. No. 3,638,723 does not disclose any mechanism to seal off the flow conductor for pressure testing. Also, the locator device, when activated, can only be secured in recesses in the flow conductor such as a landing nipple or collar recess.
The pressure testing tool of the present invention can be used in either vertical or horizontal flow conductors to test long sections for leakage. Although the present invention can be adapted for use with standard wireline equipment, it is particularly useful for TFL serviced wells which do not have vertical access. The pressure testing tool, when activated, can form a pressure barrier at any desired location within the flow conductor without having to engage a recess such as a landing nipple or collar recess between sections of the flow conductor.